Web-slitter with electronic motor control

ABSTRACT

An electronically controlled web-slitter includes dual electric motors whose functions may be controlled by an electronic controller accessed either on the chassis of the web-slitter or by way of a computer coupled to the electronic controller. Vertical and side-shift blade set-up and functions are thus accurately controlled.

CROSS-REFERENCE TO RELATED APPLICATIONS

Not applicable.

STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT

Not applicable.

NAMES OF PARTIES TO A JOINT RESEARCH AGREEMENT

Not applicable.

REFERENCE TO SEQUENCE LISTING, A TABLE, OR A COMPUTER PROGRAM LISTINGCOMPACT DISC APPENDIX

Not applicable.

BACKGROUND OF THE INVENTION Description of Related Art IncludingInformation Disclosed Under 37 CFR 1.97 and 1.98

A web-slitting machine or system typically employs a number ofweb-slitting assemblies to cut an endless moving web, such as acontinuous roll of paper or other material, into a number of strips(equal to the number of web-slitting assemblies plus one). Aweb-slitting machine of this type is shown in U.S. Pat. No. 6,732,625,which is owned by the assignee herein. The web-slitting machine supportsand permits the positional adjustment of the web-slitting assemblies,thereby permitting the machine to be configured to cut any one out of awide variety of strip width sets. A typical web-slitting assemblyincludes a web-slitter having a blade or knife that overlaps with alower anvil, so that together they present a scissors-like action to acontinuous web of material that is pulled through the assembly by a drumor a take-up reel. The web-slitter usually includes an upper carriage,which is slideably movable along a support in the form of a transversebar, and a blade holder that includes a freely rotating disk-shapedblade. The anvil, which may be in the form of a drum or roller that hasa sharpened edge, is positioned on a supporting sleeve.

The web-slitter of the '625 patent is hydraulically operated. Both thevertical motion of the blade holder and the side shift motion of theblade are controlled through hydraulic motors that are fed by fluidunder pressure. Proper set-up and alignment of the blade with the loweranvil are important. Different webs require variations in blade/anviloverlap and in lateral side-shift pressure.

Most web-slitters operate under hydraulic control, and set-up parametersmust be established manually. At least one such machine uses electricmotors to control vertical and side shift motions as shown in Germanpublication DE4130799. The aforementioned publication employs a singlemotor and complex gearing for these functions. In addition, the verticaland lateral travels of the blade are interconnected making set-up moreefficient.

BRIEF SUMMARY OF THE INVENTION

An electronically controlled web-slitter includes dual electric motorswhose functions may be controlled by an electronic controller accessedeither on the chassis of the web-slitter or by way of a computer coupledto the electronic controller. Vertical and side-shift blade set-up andfunctions are thus accurately controlled.

The foregoing and other objectives, features, and advantages of theinvention will be more readily understood upon consideration of thefollowing detailed description of the invention, taken in conjunctionwith the accompanying drawings.

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS

FIG. 1 is a schematic diagram of an electronically controlledweb-slitter using dual electric motors.

FIGS. 2A and 2B are a flow chart diagram illustrating the set-up andcalibration routine employed by the electronic controller to properlyset the blade for a cutting operation.

FIG. 3 is a side view of a web-slitter schematically illustrated in FIG.1.

FIG. 4 is a partial side cutaway view of the web-slitter of FIG. 3 withthe blade in a fully retracted position.

FIG. 5 is a partial side cutaway view of the web-slitter of FIG. 3 withthe blade in the engaged position.

FIG. 6 is a front partial cutaway view taken along line 6-6 of FIG. 4.

FIG. 7 is a front partial cutaway view taken along line 7-7 of FIG. 5.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENT

Web-slitting machinery of this type typically employs hydraulicactuators of the type shown in U.S. Pat. Nos. 5,083,489 and 6,732,625.In terms of both set-up and operation, however, hydraulically controlledcomponents lack precision and, in particular lack the precision thatwould be obtainable if an electronic controller in conjunction withelectric motors were used to control both the set-up and operation of aweb-slitting machine. By contrast, electric motors are well suited forsuch control. Such motors may take the form of stepper motors,servomotors, or vector-controlled motors. By using stepper motors, forexample, each discrete increment of movement by the motor components maybe controlled by a discrete number of digital pulses generated by anelectronic controller. The pulse count may be stored in the controller'smemory to give precise control of both vertical movement of the bladeholder relative to the carriage assembly and the side-shift motion ofthe blade. Further, the electric motors may be connected to a computerthrough an interface circuit so that commands required to executecertain functions may be controlled remotely. The computer may thencontrol an entire bank of web-slitters. Thereafter when the set-up modeis launched, each controller searches its memory for the correctsequence and pulse count needed to execute steps that cause the bladesto set up correctly and interface properly with the lower anvils.

An example of a motor-controlled web-slitter is shown in schematicdiagram form in FIG. 1. A web-slitter 10 includes a carriage 11 thathouses an electronic controller 12 having a vertical controller 12 a anda side-shift controller 12 b. Each of the controllers 12 a and 12 b hasa memory unit 14 a and 14 b respectively. The output of the controller12 is a dual-axis output. One output 16 drives a vertical motor 20. Thismotor has an output shaft 22 that is used to raise and lower ablade-holder assembly 24. The side-shift controller 12 b has a secondoutput 18, which drives a side-shift motor 26. The side-shift motor hasa vertically-extending output shaft assembly 28, which mechanicallycouples to a slitting blade 30 through a mechanical linkage 32. Thelinkage 32 converts the vertical movement in the shaft assembly 28 tohorizontal motion of the blade 30 through the linkage 32 so that it isdrawn into contact with an anvil 34.

FIG. 2 shows a set-up routine employed by a preferred embodiment inwhich information stored in the controller boards 12 a and 12 b controlsa calibration mode, which sets up the blade movement parameters forengaging the lower anvil 34. FIG. 2 illustrates the procedure for set-upand the operation of the electronic controller 12, which includes acircuit board with chip controllers and memory that execute the controlfunctions illustrated in the flow chart.

The functions of the web-slitter are controlled, either from controls onthe web-slitter itself or by an outboard computer 36. The computer 36may implement set-up, run and disengage functions and may do so for aplurality of web-slitters. Web-slitters are usually arranged in a bankalong a transverse bar predetermined distances apart. A computer, suchas computer 36, may control a plurality of web-slitters simultaneously.Alternatively, each web-slitter may be individually controlled bycontrol switches located on the carriage assembly 11. A front panelcontrol 38 has three settings: “CALIBRATE;” “ENGAGE;” and “DISENGAGE.”In addition, each carriage 11 has an up/down jog switch 40.

At start (100), the carriage 11 is positioned so that the blade 30 isslightly offset from the anvil 34. The up/down jog switch 40 is thenengaged (102). The first time the up/down jog switch 40 is engaged (whenthe blade is in an offset position relative to the anvil), the verticalmotor 20 lowers the blade-holder 24 and the side-shift motor 26 drawsthe blade 30 towards the right into a one-half stroke side-shiftposition. The blade 30 is moved manually to contact the anvil (104). TheCALIBRATE mode is then selected by control 38 and the routine starts andqueries the on-board control circuit boards 12 a, 12 b shown in FIG. 1.

The side-shift controller 12 b generates a signal to cause theside-shift motor 26 to go to its zero position (106). In this case, thezero position is the position at which the blade 30 is fully extendedaway from the anvil 34. As will be explained below, the zero position isdetected by use of a photocell circuit or other contact-type orproximity sensor. Once the side-shift motor has caused the blade 30 toreach its zero position, a command is given by the vertical controller12 a to raise the blade 30 five-eighths of an inch (0.625″) (108). Theexact distance of this step (108) is chosen only for this particularexample (as shown in the preferred embodiment) and other set-upparameters, depending upon the size of the blade and other factors, maybe chosen depending upon the application.

Once step 108 has been completed, a command is given by the side-shiftcontroller 12 b to move the blade 30 to its full-stroke position (110).Once the blade has reached full-stroke position, the vertical motormoves the blade toward the anvil (112) until the anvil is contacted(114). Once again, the contact between the blade 30 and the anvil 34 isdetected by the closing of the aforementioned electrical circuit, whichis sensed by the controller 12. During this step, the output on line 16is a series of pulses, which controls the movement of the vertical motor20. Once contact is made between the blade 30 and the lower anvil 34,the pulse count required to move this distance is stored in the verticalcontroller's memory 14 a (116). The controller then sends a signal tothe vertical motor 20 causing it to raise the blade-holder assembly 24 adistance of 0.02 inches (118). Again, this figure is chosen dependingupon the size of the blade employed and other requirements of the user.

Once step 118 has been completed, a command is given to the side-shiftmotor 26 to go to its zero point (120). The command is then given torequire the vertical motor 20 to move the blade-holder assembly 24 toits overlap position (122). The overlap position is the verticaldistance by which the blade 30 overlaps the anvil 34. This distance ischosen depending upon the size of the blade and the type of material tobe cut. Thinner, lighter materials do not require as much overlapbetween the blade and the anvil as do thicker and harder to cutmaterials. This parameter is chosen and pre-stored in the verticalcontroller's memory 14 a depending upon the requirements of the user.

A command is then given by the side-shift controller 12 b through line18 to cause the side-shift motor 26 to move the blade 30 toward theanvil 34 (124). Once contact is made with the anvil (126), the pulsecount required to do so is stored in the memory 14 b (128). It will beappreciated that, while merely touching the blade 30 to the anvil 34closes the electrical circuit and therefore stops the side-shift motor26, slight touching is inadequate for proper set-up. Therefore, frommemory 14 b a predetermined pulse count is added on line 18 to cause theside-shift motor 26 to add a certain amount of compression force for theblade 30 bearing against the anvil 34 (130). Once this occurs, the bladeis now properly set up against the anvil and a cutting operation canbegin.

At any time during the calibration process, the control 38 may be movedto either the ENGAGE or DISENGAGE position. If the control is eitherleft in the CALIBRATE position or moved to the ENGAGE position, oncestep 130 has been completed the motors stop and the unit is ready forcutting. If the DISENGAGE setting has been chosen, once step 130 hasbeen completed both the side-shift motor and the vertical motor move totheir respective positions as illustrated in steps 132 and 134.

Proper initiation of the calibration mode requires that the blade bepositioned correctly with respect to the anvil before the CALIBRATE modeis initiated. The use of the up/down jog switch 40 is provided to helpfulfill this function. However, calibration may be initiated in otherways. For example, a retractable flag could be used, which would allowfor manual positioning using the up/down jog switch 40 and movement ofthe carriage 11 along its transverse mounting bar. A retractable flag ofthis type could be a simple plastic guide member shaped to provide aninitial vertical and lateral offset between the anvil and the blade. Thestarting position may then be stored in the memory units 14 a and 14 bof the controller 12 and the calibration routines and distances formovement (in terms of numbers of pulses required to accomplish certaintasks) may be adjusted accordingly. In yet another variation, a lasermay be placed on the unit itself, which may be used to visually alignthe blade and the anvil prior to initiating the calibration mode.

The proper calibration and set-up for various applications requiresestablishing a pulse count in the memory unit 14 b of the side-shiftcontroller 12 b. In the example shown, a preset pulse count stored inmemory provides the proper side-shift compression. However, thisfunction could be accomplished automatically—for example, by measuringthe current draw on the motor for different preset side forces and theuse of an analog sensor to stop the side-shift motor when the currentdraw matches the selected preset value. In another embodiment, a loadtransducer could be used to control the side-shift motor when thetransducer measures a preset compression value.

A mechanical configuration of the preferred embodiment illustratedschematically in FIG. 1 is shown in FIGS. 3 through 7. Referring to FIG.3, a web-slitting machine 10 includes an upper carriage assembly 11 anda lower blade-holder assembly 24. The blade-holder assembly 24 supportsa rotary knife/blade 30, which bears against an anvil 34. The uppercarriage 11 is mounted for sliding movement along a transverse track 42.The control knob 38 is located on the front panel of the carriageassembly 11 along with the up/down jog switch 40. The carriage assembly11 also houses the electronic controller 12, which is coupled throughthe output lines 16 and 18 respectively to the vertical motor 20 and theside-shift motor 26. The output of the vertical motor 20 is a rotatingshaft 44, which fits into a threaded sleeve 46. The sleeve 46 includes ascrew follower that raises and lowers the blade-holder assembly 24 whenthe output shaft 44 rotates. A sleeve 48 connected to the side-shiftmotor 26 houses a rotary shaft or rod 45 which is coupled to a followerthat compresses a spring 47, which, in turn, exerts a force thatdepresses a plunger 50. The spring 47 supplies the compression forcethat biases the blade 30 against the anvil 34 in the engaged position.When the blade 30 touches the anvil 34, a spring 76 in the side-shiftpiston 74 (refer to FIG. 7) is compressed. The blade, however, cannotpress against the anvil without being allowed to give laterally with apreset amount of restoring force. The restoring force is provided by theaction of the spring 47 bearing against the plunger 50. There is aspring constant stored in the side-shift controller 12 b that links thevertical movement of the rod 45 with the amount of restoring forceprovided by the spring 47. Such formulae are well known and take intoaccount mechanical advantage provided by the other components of thelinkage 32 and friction.

The blade-holder assembly 24 is coupled to the carriage assembly 11through a dovetail fitting 52 and is locked into place by a lockinglever 54. The dovetail fitting 52 has a receiver (not shown) for theguide rod 46 and for the sleeve 48. A bellows 56 houses the guide rod 46and the sleeve 48, and expands and contracts as a result of verticalmovement of the blade-holder assembly 24. The cant angle of the blade 30(about a vertical axis) is set using a cant key 58, which is a removablekey. Keys having different shapes set the appropriate cant angle chosenby the user.

Referring to FIGS. 4 and 5, FIG. 4 shows the web-slitter 10 in its zeroposition, that is, the blade is fully upwardly retracted and theside-shift mechanism is likewise retracted. In the fully retractedposition, a spring-loaded pin 60 breaks the beam of a photocell 62. Thispin moves under the control of the side-shift linkage mechanism 32 aswill be explained below. Another photocell 64 is controlled by a pin 66,which moves in a vertical direction with the blade-holder assembly 24.When the vertical motor 20 is at its fully retracted position, the pin66 breaks the beam of the photocell 64 and turns off the vertical motor.Likewise, when the pin 60 breaks the beam of photocell 62 at the zeropoint of the side-shift mechanism, the side-shift motor 26 is turnedoff. The photocells 62 and 64 thus function as sensors to detect thefully retracted travel points as controlled by motors 20 and 26. Thephotocells 62 and 64 are connected to the electronic controller 12 byappropriate circuitry (not shown). The photocells 62 and 64 are just oneexample of sensor mechanisms that may be used to detect the limits oftravel for both the side-shift and vertical motors. Other sensors,including limit switches, electrical contacts or other types ofproximity sensors, may be used if desired.

In FIG. 5, the blade-holder assembly is fully extended and theside-shift linkage 32 has caused the blade 30 to engage the anvil 34.The output shaft (not shown) of the side-shift motor 26 pushes againstthe plunger 50, which in turn depresses a lever 68. The lever is biasedin an upwards position by a bias spring 70. When the plunger 50depresses the lever 68, the lever in turn presses downwardly against awedge member 72.

As shown best in FIGS. 6 and 7, the wedge member 72 presses against aninclined surface of a side-shift piston 74. The side-shift piston 74 isnormally biased outwardly by a spring 76. Thus, when depressed by thelever, the wedge member 72 forces the side-shift piston against thespring 76 to thereby contact the blade 30 to the anvil 34. Themechanical linkage shown in FIGS. 4 through 7 provides one example of ameans by which the movement of the vertical output rod or shaft from theside-shift motor 26 may be converted from vertical to lateral movement.Many other mechanical constructions that will perform the same functionare possible, including rack and pinion mechanisms, rotary cams or othergears that may be used to convert motion in a vertical direction tomotion in a lateral direction. In addition, since the output of theside-shift motor is rod driven by a rotary shaft, it would be possibleto link the rotary shaft directly with a gearing mechanism to providelateral side-shift motion without using the intermediary of a verticalpushrod. Many such mechanical constructions are possible.

The use of dual electric motors, one for the vertical travel of theblade-holder assembly 24 and one for the side-shift function of theblade, means that both functions may be controlled independently. Asingle motor could control both functions, but the gearing required todo so would be more complex. Independent control of both the verticalmovement of the blade and the side-shift movement of the blade insuresthat set-up and calibration may be more precisely controlled. Twocritical set-up parameters are blade/anvil overlap and the amount ofside-shift compression against the anvil. With each of these functionscontrolled by a separate electrical motor, overall accuracy of thesystem is greatly enhanced.

The terms and expressions which have been employed in the foregoingspecification are used therein as terms of description and not oflimitation, and there is no intention, in the use of such terms andexpressions, of excluding equivalents of the features shown anddescribed or portions thereof, it being recognized that the scope of theinvention is defined and limited only by the claims which follow.

1. A web-slitter for cutting a web of material, the web-slitter havingan upper blade engageable with a lower anvil and comprising: a) acarriage assembly adapted for connection to a transverse support bar; b)a blade-holder assembly coupled to the carriage assembly and including aside-shift mechanism for moving said upper blade into engagement withsaid lower anvil; c) a first electric motor mounted in said carriageassembly for raising and lowering said blade-holder assembly; and d) asecond electric motor coupled to said blade-holder assembly and havingan output shaft coupled to a side-shift piston by a linkage mechanismfor moving said blade in a lateral direction.
 2. The web-slitter ofclaim 1 wherein said linkage mechanism comprises a wedge member havingan inclined surface moveable against an inclined surface of saidside-shift piston.
 3. The web-slitter of claim 2 wherein the outputshaft moves in a vertical direction.
 4. A web-slitter for cutting a webof material, the web-slitter having an upper blade engageable with alower anvil and comprising: a) a carriage assembly adapted forconnection to a transverse support bar; b) a blade-holder assemblycoupled to the carriage assembly and including a side-shift mechanismfor moving said upper blade into engagement with said lower anvil; c) afirst electric motor mounted in said carriage assembly for raising andlowering said blade-holder assembly; and d) a second electric motorhaving an output rod or shaft moveable in a vertical direction and alinkage for converting vertical movement of said rod or shaft into alateral force to cause said side-shift mechanism to move said blade in alateral direction toward said anvil.
 5. The web-slitter of claim 4wherein said first and second motors are stepper motors and furtherincluding an electronic controller coupled to said first and secondmotors wherein said first and second motors are responsive to digitalcontrol signals generated by said electronic controller.
 6. Aweb-slitter for cutting a web of material, the web-slitter having anupper blade engageable with a lower anvil and comprising: a) a carriageassembly adapted for connection to a transverse support bar; b) ablade-holder assembly coupled to the carriage assembly and including aside-shift mechanism for moving said upper blade into engagement withsaid lower anvil; c) first and second electric motors for controlling avertical stroke of said blade-holder assembly and for controlling saidside-shift mechanism respectively; and d) an electrical sensor circuitfor stopping said first motor when said blade holder reaches apredetermined vertical position and a second electrical sensor circuitfor controlling the second electric motor for stopping the blade at apredetermined lateral position.
 7. The web-slitter of claim 6 furtherincluding an electronic controller for setting control parameters fordetermining both the vertical position and lateral force of the blade inan engaged position prior to the initiation of a cutting operation. 8.The web-slitter of claim 7 wherein said first and second electricalsensor circuits each include a photocell detector.
 9. The web-slitter ofclaim 6 wherein said second electric motor includes a verticallymoveable rod and said side-shift mechanism includes a linkage mechanismresponsive to said rod for laterally shifting said blade toward saidanvil.
 10. The web-slitter of claim 6 wherein said second electric motorincludes an output shaft and said side-shift mechanism includes alinkage mechanism for converting vertical movement of said output shaftto lateral movement of said blade.
 11. The web-slitter of claim 1further including an electronic controller coupled to said first andsecond electric motors, said electronic control having coded programinstructions for controlling the operation of said first and secondmotors to thereby engage the anvil and disengage the anvil.
 12. Theweb-slitter of claim 11 wherein said electronic controller includes acalibration program for establishing movement parameters executable forpositioning said blade against said lower anvil in preparation for acutting operation.
 13. The web-slitter of claim 12 wherein saidcalibration program includes coded instructions for determining andrecording the distances from the respective zero points of said firstand second electric motors to an engage position at which said blade ispositioned against said lower anvil.
 14. A web-slitter for cutting a webof material, the web-slitter having an upper blade engageable with alower anvil, comprising: (a) first and second electric motors forcontrolling vertical and side-shift blade movement, respectively; (b) anelectronic controller having first and second outputs for said first andsecond motors respectively; (c) first and second sensors responsive tothe zero positions of said blade in the vertical and horizontaldirections of travel, respectively, for providing first control signalsto said electronic controller; and (d) an internal circuit couplingthrough said blade and said anvil to said electronic controller whensaid blade is in contact with said anvil whereby to provide secondcontrol signals to said electronic controller.
 15. The web-slitter ofclaim 14 having a function control selector coupled to said electroniccontrol for initiating a calibration mode whereby the electroniccontroller in response to said first and second control signalsestablishes control parameters for said first and second electric motorsto cause engagement of the lower anvil with the upper blade.
 16. Theweb-slitter of claim 4 wherein said rod or shaft is coupled to saidlinkage through a spring mechanism for providing a compression force tobias said blade against said anvil with a predetermined amount of force.